Pavlovian modulation often occurs in situations where the associative relationship between conditioned stimulus (CS) and an unconditioned stimulus (US) is signaled by another stimulus. This stimulus thus provides information about the CS-US association and comes to modulate the conditioned response tot he CS. Several theories have been proposed to account for pavlovian modulation; each emphasizing the action of the modulator ont he CS, US, or CS-US association. The broad objective of the present application is to examine the Pavlovian modulatory mechanism from a different perspective from that traditionally taken by researchers in the area. Whereas previous modulation research has emphasized control exerted by the modulator over responding to the target, as exemplified by, for example, the ability of the modulator to affect responding to CSs other than the CS used in initial modulatory training, the present research will begin to examine the utility of a perspective in which the subject learns foremost appropriate responding tot he modulator's presence. This perspective is very much like that often taken in research ont he role of contexts in learning. Learning about the context is subordinate to learning about the CS. Th experiments will all involve pigeons in a Paviovian autoshaping preparation. Auditory and visual modulatory stimuli will signal occasions on which visual CSs will be followed by food unconditioned stimuli. Specific experiments will examine the conditions that promote or decrease the extent to which responding to a CS becomes specific to a modulator, and the extent to which the ability of a CS to be modulated by more than one modulator is mediated by a representation of the training modulator. Although this perspective does not account readily for all athe existing data on modulation, the contribution of such a mechanism to modulation has not been systematically examined. The results of this research should help to uncover the complex associative structure involved in modulation, and will advance our understanding of the conditions under which behavior is dependent on the learning and performance environment. The research will provide further insight into the conditions underlying behavioral control.